The last choice, "Teens who sleep less than 5 hours a night suffer from more immune related illnesses according to a study released in 2015 by the American Journal of Medicine." It gives a source to where the information had been gathered.
China.
The Silk Road is a trading route from the Middle East to China, and the ancient civilizaitons practiced ancestor worship. The Mandate of Heaven dictates that good weather and general prosperity are because of divine approval of the leader of China. If there is famine, invasion, or other natural disasters, it was interpreted as needing a new ruler, aka losing the mandate of heaven.
Relative dating is the science of determining the relative order of past events, without necessarily determining their absolute age. In geology, rock or superficial deposits, fossils and lithologies can be used to correlate one stratigraphic column with another.
Which word is bold? compliant? if so it would be dutiful.